Toward consistent seismological models of the core–mantle boundary landscape

The dynamic topography of the core-mantle boundary (CMB) provides important constraints on dynamic processes in the mantle and core. However, inferences onCMBtopography are complicated by uneven data coverage and strong lower mantle heterogeneity. Particularly, a trade-off exists with density variat...

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Main Author: Koelemeijer, P
Format: Book section
Language:English
Published: Wiley 2021
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author Koelemeijer, P
author_facet Koelemeijer, P
author_sort Koelemeijer, P
collection OXFORD
description The dynamic topography of the core-mantle boundary (CMB) provides important constraints on dynamic processes in the mantle and core. However, inferences onCMBtopography are complicated by uneven data coverage and strong lower mantle heterogeneity. Particularly, a trade-off exists with density variations, which ultimately drive mantle flow and are vital for determining the origin of mantle structures. Here, I review existing models of CMB topography and lower mantle density, focusing on seismological constraints. While most density models image two areas of dense anomalies beneath Africa and the Pacific, their exact location and relationship to seismic velocity structure differs. CMB topography strongly influences the retrieved density structure, helping to resolve differences between existing studies. Current CMB topography models vary both in pattern and amplitude, with a discrepancy between body-wave and normal-mode models. As existing models feature elevated topography below the Large-Low-Velocity Provinces (LLVPs), geodynamic predictions indicate that very dense compositional anomalies may currently be ruled out as possibility. To achieve a similar consistency as observed in S-wave and P-wave tomography models, future studies should develop models of CMB topography consistent with body-wave, normal-mode and geodetic data. This will help to break existing trade-offs with lower mantle density, thus aiding in narrowing down possible explanations for the LLVPs and providing additional insights into mantle dynamics.
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spelling oxford-uuid:d37094d8-0022-49ca-ae2c-d5d9723df4fb2022-07-06T11:11:34ZToward consistent seismological models of the core–mantle boundary landscapeBook sectionhttp://purl.org/coar/resource_type/c_1843uuid:d37094d8-0022-49ca-ae2c-d5d9723df4fbEnglishSymplectic ElementsWiley2021Koelemeijer, PThe dynamic topography of the core-mantle boundary (CMB) provides important constraints on dynamic processes in the mantle and core. However, inferences onCMBtopography are complicated by uneven data coverage and strong lower mantle heterogeneity. Particularly, a trade-off exists with density variations, which ultimately drive mantle flow and are vital for determining the origin of mantle structures. Here, I review existing models of CMB topography and lower mantle density, focusing on seismological constraints. While most density models image two areas of dense anomalies beneath Africa and the Pacific, their exact location and relationship to seismic velocity structure differs. CMB topography strongly influences the retrieved density structure, helping to resolve differences between existing studies. Current CMB topography models vary both in pattern and amplitude, with a discrepancy between body-wave and normal-mode models. As existing models feature elevated topography below the Large-Low-Velocity Provinces (LLVPs), geodynamic predictions indicate that very dense compositional anomalies may currently be ruled out as possibility. To achieve a similar consistency as observed in S-wave and P-wave tomography models, future studies should develop models of CMB topography consistent with body-wave, normal-mode and geodetic data. This will help to break existing trade-offs with lower mantle density, thus aiding in narrowing down possible explanations for the LLVPs and providing additional insights into mantle dynamics.
spellingShingle Koelemeijer, P
Toward consistent seismological models of the core–mantle boundary landscape
title Toward consistent seismological models of the core–mantle boundary landscape
title_full Toward consistent seismological models of the core–mantle boundary landscape
title_fullStr Toward consistent seismological models of the core–mantle boundary landscape
title_full_unstemmed Toward consistent seismological models of the core–mantle boundary landscape
title_short Toward consistent seismological models of the core–mantle boundary landscape
title_sort toward consistent seismological models of the core mantle boundary landscape
work_keys_str_mv AT koelemeijerp towardconsistentseismologicalmodelsofthecoremantleboundarylandscape